/*
* PROGRAM: Grader.c
* VERSION: 3.0
* AUTHOR: Alex Hamilton
* DATE: 16 NOV. 2023
*/

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#ifdef _WIN32
  #define STR_CMP_IGNORE_CASE _stricmp
  #define SYSPAUSE system("pause")
  #define CLEAR_BUFFER fflush(stdin)
#else //UNIX
  #define STR_CMP_IGNORE_CASE strcasecmp
  #define SYSPAUSE printf("\n PRESS ANY KEY TO CONTINUE..."); getchar()
  #define CLEAR_BUFFER pacMan()
#endif

void pacMan()
{
  char pacDots = '0';
  while(pacDots != '\n')
  {
    pacDots = getchar();
  }
}


struct stud
{
  char firstName[10];
  char lastName[10];
  float percentGrade;
  char letterGrade;
};
typedef struct stud STUD;

void calcPercent(float *);
void calcLabs(float *);
void calcExams(float *);
void calcFinal(float *);
void calcLetter(float, char *);

void enterStudents(STUD[], int *);
void writeScreen(STUD[], int);
void writeFile(STUD[], int, int, char[]);
void sortByGPA(STUD[], int);
void sortByName(STUD[], int);

void loadClass(STUD[], int *, char[]);
void writeClass(STUD[], int, char[]);

#define MAX_STUDENTS 30      //set to 30 when done
#define NUMBER_OF_LABS 8    //set to 8 when done
#define LAB_WEIGHT .4f
#define NUMBER_OF_EXAMS 3   //set to 3 when done
#define EXAM_WEIGHT .4f
#define FINAL_WEIGHT .2f

#define S_GPA 0
#define S_LNAME 1


main(int argc, char * argv[])
{
  STUD students[MAX_STUDENTS];
  int count = 0;
  int choice;
  char dataFileName[25];

  if(argc != 2)
  {
    printf("Incorrect Number of CL Arguments");
    SYSPAUSE;
    return(0);
  }

  sprintf(dataFileName, "%s.dat", argv[1]);

  loadClass(students, &count, dataFileName);

  do{

    printf("\n      MENU");
    printf("\n1. Enter Students");
    printf("\n2. GPA - Screen");
    printf("\n3. GPA - File");
    printf("\n4. Name - Screen");
    printf("\n5. Name - File");
    printf("\n0. EXIT");
    printf("\n\nEnter choice: ");
    scanf(" %d", &choice);
    CLEAR_BUFFER;

    switch(choice)
    {
    case 0: break;
    case 1: enterStudents(students, &count);
      break;
    case 2: sortByGPA(students, count); writeScreen(students, count);
      break;
    case 3: sortByGPA(students, count); writeFile(students, count, S_GPA, argv[1]);
      break;
    case 4: sortByName(students, count); writeScreen(students, count);
      break;
    case 5: sortByName(students, count); writeFile(students, count, S_LNAME, argv[1]);
      break;
    default: printf("\nInvalid choice\n\n");
      break;
    }
  } while(choice != 0);
  
  writeClass(students, count, dataFileName);

  printf("\n\n");
  return(0);
}

void loadClass(STUD studs[], int* count, char fname[])
{
  FILE* fpoint;
  int i = 0;
  fpoint = fopen(fname, "rb");

  if(fpoint != NULL)
  {
    fread(&studs[i], sizeof(STUD), 1, fpoint);
    while(!feof(fpoint))
    {
      i++;
      fread(&studs[i], sizeof(STUD), 1, fpoint);
    }
    *count = i;
    fclose(fpoint);
  }
}
void writeClass(STUD studs[], int count, char fname[])
{
  FILE* fpoint;
  int i;
  fpoint = fopen(fname, "wb");

  if(fpoint == NULL)
  {
    printf("Error opening file\n\n");
    SYSPAUSE;
    exit(0);
  }
  for(i = 0; i < count; i++)
  {
    fwrite(&studs[i], sizeof(STUD), 1, fpoint);
  }
  
  fclose(fpoint);
}

void calcPercent(float *ptr_percent)
{
  float labs;
  float exams;
  float final;
  calcLabs(&labs);
  calcExams(&exams);
  calcFinal(&final);
  *ptr_percent = labs + exams + final;
}
void calcLabs(float * ptr_labs)
{
  float currentScore;
  int lab_nbr = 1;
  float totalScore = 0;
  while(lab_nbr <= NUMBER_OF_LABS)
  {
    printf("Enter the score for Lab %d: ", lab_nbr);
    scanf("%f", &currentScore);
    CLEAR_BUFFER;
    totalScore += currentScore;
    lab_nbr++;
  }
  *ptr_labs = totalScore / NUMBER_OF_LABS * LAB_WEIGHT;
}
void calcExams(float * ptr_exams)
{
  float currentScore;
  int exam_nbr = 1;
  float totalScore = 0;
  while(exam_nbr <= NUMBER_OF_EXAMS)
  {
    printf("Enter the score for Exam %d: ", exam_nbr);
    scanf("%f", &currentScore);
    CLEAR_BUFFER;
    totalScore += currentScore;
    exam_nbr++;
  }
  *ptr_exams = totalScore / NUMBER_OF_EXAMS * EXAM_WEIGHT;
}
void calcFinal(float *ptr_final)
{
  float score;
  printf("Enter the score for the Final: ");
  scanf("%f", &score);
  CLEAR_BUFFER;
  *ptr_final = score * FINAL_WEIGHT;
}
void calcLetter(float percent, char *ptr_letter)
{
  if(percent >= 94) {
    *ptr_letter = 'A';
  }
  else if(percent >= 85) {
    *ptr_letter = 'B';
  }
  else if(percent >= 75) {
    *ptr_letter = 'C';
  }
  else if(percent >= 65) {
    *ptr_letter = 'D';
  }
  else {
    *ptr_letter = 'F';
  }
}

void enterStudents(STUD students[], int *ptr_count)
{
  if(*ptr_count == MAX_STUDENTS)
  {
    printf("\nMaximum class size reached. No more students allowed.\n");
    SYSPAUSE;
  }
  
  while(*ptr_count < MAX_STUDENTS)
  {
    printf("\nEnter student FIRST name or (0) to Exit: ");
    scanf(" %9s", students[*ptr_count].firstName);
    CLEAR_BUFFER;

    if(strcmp(students[*ptr_count].firstName, "0") == 0)
    {
      break;
    }

    printf("Enter student LAST name: ");
    scanf(" %9s", students[*ptr_count].lastName);
    CLEAR_BUFFER;

    calcPercent(&students[*ptr_count].percentGrade);
    calcLetter(students[*ptr_count].percentGrade, &students[*ptr_count].letterGrade);
    
    *ptr_count = *ptr_count + 1;
    if(*ptr_count == MAX_STUDENTS - 1) printf("\nWARNING: You can only enter 1 more student\n");
  }
}
void writeScreen(STUD students[], int count)
{
  int i;
  printf("\n   GRADE REPORT\n");
  printf("LAST       FIRST       %% GRADE    LETTER GRADE");
  for(i = 0; i < count; i++)
  {
    printf("\n%-9s  %-9s %9.2f %10c", students[i].lastName, students[i].firstName, students[i].percentGrade, students[i].letterGrade);
  }

  printf(count == 1 ? "\n\n   TOTAL: %d STUDENT" : "\n\n   TOTAL: %d STUDENTS", count);
  printf("\n\n");
}
void writeFile(STUD students[], int count, int sortedBy, char className[])
{
  FILE* fout;
  char fileName[25];
  int i;

  if(sortedBy == S_GPA)
  {
    sprintf(fileName, "%s_GPA.txt", className);
    fout = fopen(fileName, "w");
  }
  else
  {
    sprintf(fileName, "%s_LName.txt", className);
    fout = fopen(fileName, "w");
  }
  if(fout == NULL)
  {
    printf("\nError opening file!");
    printf("\nPress any key to exit the program.");
    CLEAR_BUFFER; SYSPAUSE;
    exit(1);
  }

  fprintf(fout, "   GRADE REPORT\n");
  fprintf(fout, "LAST       FIRST       %% GRADE    LETTER GRADE");

  for(i = 0; i < count; i++)
  {
    fprintf(fout, "\n%-9s  %-9s %9.2f %10c", students[i].lastName, students[i].firstName, students[i].percentGrade, students[i].letterGrade);
  }

  fprintf(fout, count == 1 ? "\n\n   TOTAL: %d STUDENT" : "\n\n   TOTAL: %d STUDENTS", count);
  printf("Report successfully created\n");
  fclose(fout);
}
void sortByGPA(STUD students[], int count)
{
  STUD temp;
  int i, x;
  for(x = 0; x < count; x++)
  {
    for(i = 0; i < count - 1 - x; i++)
    {
      if(students[i].percentGrade < students[i + 1].percentGrade)
      {
        temp = students[i];
        students[i] = students[i + 1];
        students[i + 1] = temp;
      }
    }
  }
}
void sortByName(STUD students[], int count)
{
  STUD temp;
  int i, x;
  for(x = 0; x < count; x++)
  {
    for(i = 0; i < count - 1 - x; i++)
    {
      if(STR_CMP_IGNORE_CASE(students[i].lastName, students[i + 1].lastName) > 0)
      {
        temp = students[i];
        students[i] = students[i + 1];
        students[i + 1] = temp;
      }
      if(STR_CMP_IGNORE_CASE(students[i].lastName, students[i + 1].lastName) == 0 &&
         STR_CMP_IGNORE_CASE(students[i].firstName, students[i+1].firstName) > 0)
      {
        temp = students[i];
        students[i] = students[i + 1];
        students[i + 1] = temp;
      }
    }
  }
}